Just remembered you guys asked for this: Highway RPM's with 3.73's

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Oct 17, 2000 | 02:52 PM

TomP

Thread Starter

Supreme Member

Joined: Mar 2000

Posts: 13,414

Likes: 6

From: Central NJ, USA

Car: 1986 Firebird

Engine: 2.8 V6

Transmission: 700R4

Just remembered you guys asked for this: Highway RPM's with 3.73's

Rear gear: 3.73/posi
Rear tires: 275/60r15 (28 inches diameter)

Technically, those above two specs give me an "effective" rear gear ratio of 3.46.

All RPM measurements were taking with light throttle (not coasting) in overdrive (4th gear), 1.0:1 ratio.

55 MPH = 1800 RPM
65 MPH = 2000 RPM
80 MPH = 2200 PRM

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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

Oct 17, 2000 | 06:08 PM

85f-bird

Supreme Member

Joined: Mar 2000

Posts: 2,028

Likes: 0

From: St. Louis, MO

Car: 85' Firebird (Project), 92' RS

Engine: 2.8L, LS1

Transmission: 700R4, 4L60E

Axle/Gears: 3.42 Open , 10 Bolt (ukn)

looks like 2nd and 3rd gear to me, j.k. well the rpms would be higher. That doesn't sound half bad. How's your gas millage right now since the swap. And are you still enjoying the new rear end? if not gank it, and ship it to St.Louis

Oct 17, 2000 | 11:06 PM

Kevin S

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Joined: Jan 2000

Posts: 384

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From: Pt. Pleasant, WV (Home of the Mothman!)

Thats close to what I run with 215/60's.I wouldn't want to imagine what I would be running with 3.73's.
At 55 I'm running 1750rpm's(give or take).

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